Laminated material



f Feb. 9, 1932. G, H, MANS 1,844,512

LAMINATED MATERIAL Filed Oct. 1l, 1929 INVENTOR Gerald H.Mans

` ATfoRNEY UNITED STATES PATENT -oFFlcE GERALD E. IAINS, O F MUBBYBVILLE, PENNSYLVANIA, ASSIGNOB T0 'WESTIN'GHOUBE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION 0F IENNSYLVANIA 'LAIINATED MATERIAL Application led October 11, 1929. Serial No. $88,928.

vMy invention relates to laminated material and Amore particularly to comgiosite laminated structures comprising lreen orced sheets of fibrous material and to the process ofv producing same. l

. An' object of my invention is to produce a laminated structure comprising one or more metallic strips -having a roughened or etched surface, to which sheets or strips of fibrous material, impre ated with a suitable binder, such as a pheno ic condensation product, are molded under heat and pressure to form a composite article.

Another object of my invention is to provlde'an improved method of securely uniting fibrous sheet material to a metallicmember which comprises treating'the metallic mem berto produce a roughened or etched surface and then molding sheets of fibrous material on the roughened surface under sufficient heat and pressure to produce a unitary, laminated structure having a high tensile strength.

Another and more specific object of my in vention is to provide an improved method of uniting laminated sheet material to strips or sheets of metal which com rises treating the metal with a suitable rouglibning a ent, such as a. sand blast, to produce an in ented or uneven surface, immersing the sheet or strip in a picklin hath to clean and further etc the materia rinsing and drying the metal to produce a clean surface and finally molding .fibrous sheet material, impregnated with a suitable binder, such as a phenolic condensation product, upon the roughened surface, under heat and pressure, to form a composite article.

yIt has heretofore been proposed to mold metallic sheets or strips into laminated products for the purpose of the material and increasing its itiiculty, however, strong joint betweenthe fibrous sheet material and the metallic member and this is especially true when the structure is made from comparatively thin Vsheets of material.

I have made the discovery that, if the metal is roughened or etched in a suitable manner, strips or sheets of fibrous material, impregreenforcing) strength.

applications.

has been experienced in securing a nated with a binder that is capable of being hardened under heat and pressure, may be securely united to the faces of the metal sheets to form a strong unitary structure.

My invention may be utilized in various For instance, it is particularly valuable in aeroplane construction, where maximum strength and stiifnessfor a minimum weight is re uired. It may also be utilized in structura elements, such as panels, angles, channels, tubes,vor the like, or it may be employed in providing protective or decorative covers for the surfaces, of containers.

My linvention will be better understood by reference to the accompanying drawings, in

which Fig. l is a perspective view'of a metallic sheet that has been roughened on one face and a plurality of sheets of fabric material that have been impregnated with a phenolic condensation product.

ig. 2 is a cross sectional view of a molded laminated structure showing the fibrous materialV molded toy the roughened face of the metallic sheet.

Fig. 3 is a similar View of a laminated structure showing a sheet of metal roughened on both faces and fibrous material molded thereto.

Fig. 4 is a cross sectional view of a molded laminated structure showing alternate layers of metal having roughened surfaces on both sides and alternate layers of fibrous sheet material molded to the metal.

Figs. 5 and 6 are cross sectional views of structural elements .each showing a metallic element having a rou hened surface to which ,fibrous sheet materia has been molded.

Figs. 7 and 8 are perspective view's tively, partially in cross section, of an and respeca pipe tallic sheet that has been roughened by a sand blast and etched with an acid.

In practicing my invention, the metal sheet or strip 1 1s first roughened by any suitable means, such as a sand blast. The sand or grit employed for this treatment may vary considerably in size but I prefer to utilize a container made in a similar manner;

Fig. 9 is an exaggerated-side vview of a medilute solution of sulphuric or nitric acid,

is suitable for this pur ose. 'Ihe plate is then rinsed in water an permitted to dry.'

This treatment forms an irregular etched.

surface that is partially sulphated or oxidized.

The fibrous sheet material is preparedby the usual process which consists in first impregnatin the sheets with a suitable binder, such as p enolic condensation product, and then drying the sheets at a suiiicient temperature to eliminate the solvent without hardening the binder. A plurality of sheets of the impregnated fibrous material is then placed on one or both sides of the metallic sheet and the layers consolidated, under heat and pressure, into a unitary, composite structure. Y

A pressure of 500 pounds to 2,000 pounds per square inch and a tem erature of 100 C. to 180 C. are suitable. he heat causes the 'binder to flow, and the pressure forces the fibrous material into the indented and etched portions of the plates. The partially sulphated or oxidized surface adhesion between the fibrous sheetmaterial and the metal.

Upon the application of continued heat and pressure, the binder is solidified to f orm a composite structure that is strong and rigtid. My improved process is particular y valua .le for aeroplane structure because composite elements or plates that are comparatively thin in cross section and have greater strength than the molded material and greater rigidity than metal of the same weight may be produced. The fibrous material a o protects the metal from corrosion and permits the formation of decorative effects.

Referring to Figs. 1, 2 and 3 of the drawings, the -numeral 1 designates a metal sheet that has been roughened and etched in preparationfor the molding process and the numeral 2 the consolidated layers of fibrous material. As shown in Fig. 2, the fibrous material is molded to only one side of the metal sheet 1. In such structures, it is of course` only necessary to roughen or etch one side of the metallic sheet but, when laminated structures are desired having fibrous material on both sides of the metal, as shown in Figs. 3

and 4, the metal will be roughened or etched on both sides. In Figs. 5, y6, 7 and 8 of the drawings, examples vare given which illustrate various articles that may beconstructed in accordance with my improved process. Figs. l5, 6 and 7 respectively show an angle iron 4, a channel 5 and a pipe ortube 6, having fibrous material molded on the outside, and Fig. 8 illustrates a container having also increases thel ifnolded material on both inner and outer suraces.

Since the method of producing a roughened surface may beaccomplished by various means, I do not desire to be limited in this res ect. For instance, heavy metal'rollers having suitable projections may be utilized for scoring, roughening or undercutting the surface of the metal, or other 'suitable mechanical means may be employed, such as a heavy wire brush. I prefer, however, to utilizethesand-blasttreatmentforroughening the surface of the metal and to-further etch it b means of a suitable acid bath. The san -blast treatment is economical andhas the tendency to undercut the surface of the metal as shown in Fig. 9 of the drawings, The roughened ortions are then further etched by meanso acid. An undercut rou hened surface has a particular advantage ecause thebrous material has a greater coeiiicient of contraction than the metal and, during the cooling of the' composite plate in the molding process, it will, accordin ly, be securely anchored in the indentations rmed on the surface of the metal.

'Ihe plickling bath to be utilized will depend u on t e metal employed as the reenforcin e ement. For example, when a ferrous meta such as iron or stee is employedrthe standard sulphuric-acid pickling bath is very satisfactory. When copper is utilized, a pickling bath comprising a mixturey of sulghuric and nitric acids gives good results.

or etching aluminum or aluminum alloys, I prefer to utilize an aqueous solution of hydrochloric acid as the etching agent. pickling bath, such as sulphuric or nitric acid, is preferred when it is capable of etching the particular metal desired because these baths have the tendenc to roduce a partially oxidized or sul hate sur ace which increases the adhesion tween the metallic sheet and the fibrous materiall during the molding o rations.

While have described myy invention in considerable detail, it will be understood that I do not desire to be limited to the exact process and structure disclosed. For example, the' moldable` material may consist of Afibrous sheet material or it may consist of agglomerated material, such as chopped, punched or shredded cloth duck, pa r or other fibrous material, hat as been im regnated with a suitable binder, such as a p enolic condensation roduct.

Ot er modifications of m invention will become a parent to those ski led in the art.y I desire t erefore, that only such limitations shall be imposed on my invention as are reui red by the prior art and the appended c aims.

I claim as my invention:

1. The method of forming a laminated 'structure comprising a layer' of metal and a 13 layer of fibrous material which comprises treating the layer of metal to form an indented surface, impregnating the fibrous ture to sufficient heat and pressure to forcev a portion of the fibrous material into said indentations and to harden the binder, there by securely anchoring the layer of fibrous material to the layer of metal.

2. The method of forming a laminated structure comprising a layer of metal and a plurality of layers of fibrous material impregnated with a fusible binder capable of being hardened when heated, which comprises treating the layer of metal to form indented surfaces on both sides, assembling the fibrous material on each side of the layer of metal and molding the assembled layers, under heat and pressure, to form a composite structure, sufiicient heat and pressure being applied to force the fibrous material into the indentations and tol harden the binder, thereby se- 'curely anchoring the bres to the indenta- 3. A laminated material comprising a layer of fibrous material and a sheet or strip of metal having a surface provided With indentations, a portion of said fibrous material eX- tending into said indentations and being'securely anchored thereto.

4. A laminated material comprising a layer of fibrous material and a sheet or strip of metal provided with indentations, a portion of said fibrous material extending into said indentations and being securely anchored thereto by means of a heat-hardened binder.

5. A laminated material comprising a layer of fibrous material and 4a sheet or strip of metal provided with a surface having etched indentations, a portion of said fibrous material extending into said indentations and being securely anchored thereto by means of a heat-hardened binder.

6. A laminated material comprising a plurality of layers of fibrous material and a sheet of metal having both of its surfaces provided with indentations, a portion of each of the layers of said fibrous material extending into said indentations and being securel anchored thereto by means of a heat-har ened binder. f 4 I 7. The method of forming a laminated structure comprising a layer of metal and a layer of fibrous material which comprises treating the layer of metal to form an indented surface, impregnating the fibrous material with a solution of a binder capable ofbeing hardened under heat and pressure, par tially drying the impregnated fibrous material at a sufficient temperature to eliminate the solvent without hardening the binder, assembling the layers and finally applying sufficient heat and pressure to force a portion of thefbrous material into said indentations and harden the binder thereby securely anchoring the layer of fibrous material to the layer of metal.

8. The method of forming a laminatedl structure comprising a layer of metal and a layer of fibrous material which comprises treating the layer of metal with a roughening agent capable of forming undercut indentations, etching the surface of the indentations, impregnating the fibrous material with a solution of a binder capable of being hardened under heat and pressure, partially drying the impregnated fibrous material at a sufficient temperature to eliminate the solvent `without hardening the binder, assembling the layers and finally applying sufficient heat and pressure to force a portion of the fibrous material into said indentations and harden the binder, thereby securely anchoring the layer of fibrous Amaterial to the layer of metal.

9. The method of forming a laminated structure comprising a layer of metal and a layer of fibrous material which comprises treating the layer of metal with a sand blast with sand of such a size and in such a manner that undercut indentations will be formed, etching the surface of said indentations with an acid, impregnating the fibrous material With asolution of a binder capable of being hardened under heat and pressure, partially drying the impregnating fibrous material at a sufficient temperature to eliminate the solvent without hardening the binder, assembling the layers and finally applying sufiicient heat and pressure to force a portion of the fibrous material into said indentations GERALD H.- MAINS. 

